1. Field of the Invention
The present invention relates generally to a microstrip antenna for use on a weapons system to transmit telemetry data from the weapons system. More specifically, the present invention relates to a microstrip antenna which has mode suppression slots and which is adapted for use on a weapons system such as a missile.
2. Description of the Prior Art
There is currently a need for a microstrip antenna for use in a small diameter projectile and for transmitting telemetry data while suppressing unwanted modes of operation. Normally, microstrip antennas exhibit many modes of operation, that is microstrip antennas will work at multiple frequencies depending upon their construction. A problem occurs when the microstrip antenna is designed to radiate at one mode of operation and not at a frequency band that is outside of the desired mode of operation.
For the desired mode of operation which is 2.250 GHz, the noise radiated by a TM microstrip antenna at the GPS L-1 band (1.575 GHZ) is high enough to raise the effective noise floor to a GPS receiver to substantially reduce the effectiveness of the GPS receiver.
Thus, there is need to suppress the unwanted noise radiated by the TM microstrip antenna to allow the GPS receiver and its associated antenna to operate effectively at the GPS L-1 band.